Design of an Innovative CFS Purlin (Zigmax®) by Experimental Testing

Abstract ZIGMAX® is an innovative cold‐formed steel solution developed for roof purlins stabilized by steel sheeting or sandwich panels. This hybrid cross‐section merges the benefits of traditional Z and Σ profiles, delivering improved structural performance. Its design enables two profiles to form a closed central core, enhancing strength, stiffness, and versatility. This study evaluated the structural behaviour of the ZIGMAX® cross‐section through experimental testing in line with EN 1993‐1‐3, Annex A, clause A.3.4. Four‐point bending tests were performed with lateral restraints at the interfaces between the ZIGMAX® purlin and the sheeting or panel. The test campaign considered multiple parameters, including span lengths, thicknesses, cross‐sectional dimensions and configurations (built‐up sections), and lateral restraint spacing. A total of 19 specimens were tested to assess load‐bearing capacity and failure modes. Results were compared against design predictions per EN 1993‐1‐3 and it was observed that the design predictions were conservative for all tested configurations. The ZIGMAX® system offers a promising alternative for modern construction, combining structural efficiency with potential economic benefits.